 /*******************************************************************************
  * Copyright (c) 2000, 2006 IBM Corporation and others.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
  * http://www.eclipse.org/legal/epl-v10.html
  *
  * Contributors:
  * IBM Corporation - initial API and implementation
  *******************************************************************************/
 package org.eclipse.text.edits;

 import java.util.List ;

 import org.eclipse.core.runtime.Assert;

 import org.eclipse.jface.text.BadLocationException;
 import org.eclipse.jface.text.IDocument;
 import org.eclipse.jface.text.IRegion;

 /**
  * A multi-text edit can be used to aggregate several edits into
  * one edit. The edit itself doesn't modify a document.
  * <p>
  * Clients are allowed to implement subclasses of a multi-text
  * edit.Subclasses must implement <code>doCopy()</code> to ensure
  * the a copy of the right type is created. Not implementing
  * <code>doCopy()</code> in subclasses will result in an assertion
  * failure during copying.
  *
  * @since 3.0
  */
 public class MultiTextEdit extends TextEdit {

     private boolean fDefined;

     /**
      * Creates a new <code>MultiTextEdit</code>. The range
      * of the edit is determined by the range of its children.
      *
      * Adding this edit to a parent edit sets its range to the
      * range covered by its children. If the edit doesn't have
      * any children its offset is set to the parent's offset
      * and its length is set to 0.
      */
     public MultiTextEdit() {
         super(0, Integer.MAX_VALUE);
         fDefined= false;
     }

     /**
      * Creates a new </code>MultiTextEdit</code> for the given
      * range. Adding a child to this edit which isn't covered
      * by the given range will result in an exception.
      *
      * @param offset the edit's offset
      * @param length the edit's length.
      * @see TextEdit#addChild(TextEdit)
      * @see TextEdit#addChildren(TextEdit[])
      */
     public MultiTextEdit(int offset, int length) {
         super(offset, length);
         fDefined= true;
     }

     /*
      * Copy constructor.
      */
     protected MultiTextEdit(MultiTextEdit other) {
         super(other);
     }

     /**
      * Checks the edit's integrity.
      * <p>
      * Note that this method <b>should only be called</b> by the edit
      * framework and not by normal clients.</p>
      *<p>
      * This default implementation does nothing. Subclasses may override
      * if needed.</p>
      *
      * @exception MalformedTreeException if the edit isn't in a valid state
      * and can therefore not be executed
      */
     protected void checkIntegrity() throws MalformedTreeException {
         // does nothing
 }

     /**
      * {@inheritDoc}
      */
     final boolean isDefined() {
         if (fDefined)
             return true;
         return hasChildren();
     }

     /**
      * {@inheritDoc}
      */
     public final int getOffset() {
         if (fDefined)
             return super.getOffset();

         List /*<TextEdit>*/ children= internalGetChildren();
         if (children == null || children.size() == 0)
             return 0;
         // the children are already sorted
 return ((TextEdit)children.get(0)).getOffset();
     }

     /**
      * {@inheritDoc}
      */
     public final int getLength() {
         if (fDefined)
             return super.getLength();

         List /*<TextEdit>*/ children= internalGetChildren();
         if (children == null || children.size() == 0)
             return 0;
         // the children are already sorted
 TextEdit first= (TextEdit)children.get(0);
         TextEdit last= (TextEdit)children.get(children.size() - 1);
         return last.getOffset() - first.getOffset() + last.getLength();
     }

     /**
      * {@inheritDoc}
      */
     public final boolean covers(TextEdit other) {
         if (fDefined)
             return super.covers(other);
         // an undefined multiple text edit covers everything
 return true;
     }

     /*
      * @see org.eclipse.text.edits.TextEdit#canZeroLengthCover()
      */
     protected boolean canZeroLengthCover() {
         return true;
     }

     /*
      * @see TextEdit#copy
      */
     protected TextEdit doCopy() {
         Assert.isTrue(MultiTextEdit.class == getClass(), "Subclasses must reimplement copy0"); //$NON-NLS-1$
 return new MultiTextEdit(this);
     }

     /*
      * @see TextEdit#accept0
      */
     protected void accept0(TextEditVisitor visitor) {
         boolean visitChildren= visitor.visit(this);
         if (visitChildren) {
             acceptChildren(visitor);
         }
     }

     /*
      * @see org.eclipse.text.edits.TextEdit#adjustOffset(int)
      * @since 3.1
      */
     void adjustOffset(int delta) {
         if (fDefined)
             super.adjustOffset(delta);
     }

     /*
      * @see org.eclipse.text.edits.TextEdit#adjustLength(int)
      * @since 3.1
      */
     void adjustLength(int delta) {
         if (fDefined)
             super.adjustLength(delta);
     }

     /*
      * @see TextEdit#performConsistencyCheck
      */
     void performConsistencyCheck(TextEditProcessor processor, IDocument document) throws MalformedTreeException {
         checkIntegrity();
     }

     /*
      * @see TextEdit#performDocumentUpdating
      */
     int performDocumentUpdating(IDocument document) throws BadLocationException {
         fDelta= 0;
         return fDelta;
     }

     /*
      * @see TextEdit#deleteChildren
      */
     boolean deleteChildren() {
         return false;
     }

     void aboutToBeAdded(TextEdit parent) {
         defineRegion(parent.getOffset());
     }

     void defineRegion(int parentOffset) {
         if (fDefined)
             return;
         if (hasChildren()) {
             IRegion region= getCoverage(getChildren());
             internalSetOffset(region.getOffset());
             internalSetLength(region.getLength());
         } else {
             internalSetOffset(parentOffset);
             internalSetLength(0);
         }
         fDefined= true;
     }

     /*
      * @see org.eclipse.text.edits.TextEdit#internalToString(java.lang.StringBuffer, int)
      * @since 3.3
      */
     void internalToString(StringBuffer buffer, int indent) {
         super.internalToString(buffer, indent);
         if (! fDefined)
             buffer.append(" [undefined]"); //$NON-NLS-1$
 }
 }

